Forget cooking your own dinners or investing in a 401(k). The official sign that you've reached adulthood is a nice, stylish apartment. You know, one that's worthy of having mom come and stay for the weekend. Maybe you were born with design instinct or maybe it took you a few years to get it right, but either way, you've done it. How do you know? Because you no longer sleep on a futon or hang your art with tape. For even more assurance, we're breaking down all the signs that prove you're living like a bona fide adult. Now that deserves a drink!